1. Field of the Invention
This invention relates generally to mechanisms for winding self-winding mechanical watches. In particular, the invention describes an automatic watch-winding apparatus for keeping a self-winding watch wound during periods of non-use.
2. General Background and State of the Art
Self-winding watches have been available for many years and are known for keeping a mechanical wrist watch wound while it is worn by a user. The winding mechanism of a self-winding watch typically comprises a rotary pendulum or rotor that is connected through a gear reduction system to a mainspring adapted to drive the escape mechanism of the watch. The pendulum pivots about a bearing and is generally capable of rotating a full 360 degrees. When the watch is worn, the random movements of the wearer cause the rotor to oscillate back and forth, or to spin completely about its axis, to wind the mainspring. When completely wound, the mainspring will generally have sufficient energy to run the watch for up to about 12 to 48 hours, depending on the particular type of watch. Some watches can store enough energy to run eight days. In any event, the daily use of the watch will normally be sufficient to maintain continuous operation overnight, even if no winding takes place at night. However, it is not uncommon for a person to own more than one watch, for use on different occasions such as sporting events, formal attire, or office attire. Thus it will be appreciated that if one watch in a collection of watches is not worn for a few days, the energy in its mainspring will completely dissipate. Once the spring is unwound, a self-winding watch cannot, as can a manually wound watch, be fully rewound in a few seconds by the user. The task of maintaining multiple watches wound and operating is an inconvenience, and may also include resetting the time on the watch each time the spring runs down. Thus, the owner of a self-winding watch may rely on a watch winder to wind the watch during periods of non-use.
A watch winder is a powered device designed to keep a self-winding watch wound, thereby eliminating the need for manual rewinding and resetting. Prior art watch winders typically include a power driven spindle or turntable adapted to hold and rotate the watch about an axis coincident with its center. During rotation, the pendulum or rotor of the watch will hang downward under gravity, and the watch will rotate about the stationary rotor. In certain prior art winders, an electronic circuit is provided to start and stop the movement of the spindle. Yet, a number of problems are encountered in the prior art. Typically, the control circuit of a prior art watch winder is configured to permit the spindle to rotate for a set period of time. This may be unproblematic for most self-winding watches, but where the watch is large or heavy, the weight of the watch may cause the powered winding mechanism to slow down, resulting in the watch being not completely wound after the spindle ceases turning. Further, some watch winders provide more than one spindle to run off a single DC battery or power source. When more than one spindle is being powered, the speed of rotation of both spindles may be slower than when only one spindle is being powered off the same power source. These factors introduce problems for watch winding mechanisms configured to run for a set period of time. Power fluctuations, as well as battery strength, can also affect the speed of rotation.
A further problem may be encountered with prior art watch winders if, for example, a user places his watch in a winder and starts it running intending to leave the watch in the winder for, say, 36 hours before he wears it. If the watch takes only 12 hours to wind, then 24 hours may be spent winding a fully wound watch. This is an inefficient use of battery energy, and may even be mechanically undesirable for the watch. Alternatively, under the same circumstances, if the user places his watch in a winder knowing it is fully wound, then 36 hours may be spent winding a fully wound watch, to even greater wasteful effect. The prior art has not sufficiently taken into account such questions of battery efficiency. Further, the prior art has not adequately provided for various aspects of convenient use, such as where different watch types have mechanisms with different winding requirements.
Problems can be encountered in that certain self-winding watches may have a plurality of spring mechanisms, or so-called “complications,” dedicated to running separate features of the watch. For example, a first spring mechanism may be dedicated to running the hour and minute hands of the watch, while a second spring mechanism may be dedicated to running the calendar and the lunar phase indicator. Where such separate spring mechanisms are included, they may be configured to be wound in opposite directions. Thus, it may be necessary for a watch-winder to rotate, alternately, clockwise and counterclockwise in order to wind both spring mechanisms. However, some self-winding watches are only wound by the rotor rotating in one direction, either clockwise, or anticlockwise, so that alternating the direction of rotation may actually amount to a waste of battery energy in the case of such watches. Furthermore, in the prior art, certain known watch winders rotate only a single revolution in one direction and then pause for a period of approximately a minute before rotating a single revolution in the other direction to be followed by another pause of approximately one minute, and so on, thus repeating the pattern until the unit is deactivated. This pattern of intermittent operation with frequent starts and stops, while adequate to wind many self winding watches, has the disadvantage of resulting in an inefficient use of stored battery power.
Thus, a need exists for an improved watch winder that will address the needs of the prior art. It is believed that the present invention fulfills all of these needs.